Ink jet printing has become a prominent contender in the digital output arena because of its non-impact, low-noise characteristics, and its compatibility with plain paper. Ink jet printings avoids the complications of toner transfers and fixing as in electrophotography, and the pressure contact at the printing interface as in thermal resistive printing technologies. Ink jet printing mechanisms includes continuous ink jet or drop-on-demand ink jet. U.S. Pat. No. 3,946,398, which issued to Kyser et al. in 1970, discloses a drop-on-demand ink jet printer which applies a high voltage to a piezoelectric crystal, causing the crystal to bend, applying pressure on an ink reservoir and jetting drops on demand. Piezoelectric ink jet printers can also utilize piezoelectric crystals in push mode, shear mode, and squeeze mode. EP 827 833 A2 and WO 98/08687 disclose a piezoelectric ink jet print head apparatus with reduced crosstalk between channels, improved ink protection, and capability of ejecting variable ink drop size.
Great Britain Patent 2,007,162, which issued to Endo et al. in 1979, discloses an electrothermal drop-on-demand ink jet printer which applies a power pulse to an electrothermal heater which is in thermal contact with water based ink in a nozzle. A small quantity of ink rapidly evaporates, forming a bubble which causes an ink drop to be ejected from small apertures along the edge of the heater substrate. This technology is known as Bubblejet.TM. (trademark of Canon K. K. of Japan).
U.S. Pat. No. 4,490,728, which issued to Vaught et al. in 1982, discloses an electrothermal drop ejection system which also operates by bubble formation to eject drops in a direction normal to the plane of the heater substrate. As used herein, the term "thermal ink jet" is used to refer to both this system and system commonly known as Bubblejet.TM..
One advantage of ink jet printing is its capability in printing large-format images. A relatively narrow print head can print a large image on a receiver by scanning across the large printing area in multiple passes. The currently commercial large-format ink jet printers can provide ink images in the widths of 36" to 62". In contrast, a thermal resistive printer utilizes a page-wide print head. The colorants are transferred from a donor web to a receiver at the pressure contact interface between the page-wide print head and the receiver. The manufacturing difficulties and cost make it unfeasible for thermal resistive print head to be wider than a double-page size.
The advancement of ink jet printing technologies has also opened up opportunities in photographic printing for applications in photo minilabs and photo microlabs. In these environments, the ink jet printing techniques have the advantages of easy image manipulation, compatibility with digital image files, and faster turn-around time. When configured properly, ink jet printers can deliver images with qualities comparable to that of the traditional photographs. The typical photographic formats include 3R (3.5".times.5"), 4R (4".times.6"), page size (8.5".times.11") etc. For a given width (e.g. 3.5", 4", 5"), the image length can also vary (e.g. from 5" to 12") from Classic, to HDTV and Panoramic format.
In commercial ink jet printing, it is very desirable to have one ink jet printer to print ink images in both large formats (3'.times.4') and traditional photographic formats. The service provider can then provide traditional photographs with added digital features and flexibility as well as poster-sizes ink images for displays for home, offices, signage, and graphic art applications.